The normal way to operate a drinking bird is to have him dip his head in water. The water on his felt head evaporates, leaving the head cooler than the bird’s body. The liquid flowing into the upper bulb (head) changes the center of gravity, causing the bird to tip forward. Liquid flows back to the bottom bulb and the bird returns to his upright position. As long as an adequate temperature difference (head cooler than body) remains, the cycle will repeat.

Instead of cooling the head, why not warm the body? If you place an electrical resistor below the bird’s body and pass current through the resistor, the resistor will get warm. The warmth will cause the bird to bob. Read the rest of this entry »